services: Cleanup class/struct fwd declarations

services/ui/public/cpp/window_tree_client_delegate.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef SERVICES_UI_PUBLIC_CPP_WINDOW_TREE_CLIENT_DELEGATE_H_
 #define SERVICES_UI_PUBLIC_CPP_WINDOW_TREE_CLIENT_DELEGATE_H_
 
 #include <string>
 
 #include "services/service_manager/public/interfaces/interface_provider.mojom.h"
 #include "services/ui/public/interfaces/window_tree.mojom.h"
 
 namespace ui {
-class Event;
-}
-
-namespace ui {
 
 class Window;
 class WindowTreeClient;
 
 // Interface implemented by an application using mus.
 class WindowTreeClientDelegate {
  public:
   // Called when the application implementing this interface is embedded at
   // |root|.
   // NOTE: this is only invoked if the WindowTreeClient is created with an
@@ skipping 24 matching lines @@
   virtual void OnPointerEventObserved(const ui::PointerEvent& event,
                                       Window* target) = 0;
 
  protected:
   virtual ~WindowTreeClientDelegate() {}
 };
 
 }  // namespace ui
 
 #endif  // SERVICES_UI_PUBLIC_CPP_WINDOW_TREE_CLIENT_DELEGATE_H_